This invention relates to lasers and in particular to lasers thermally pumped using rare earth selective emitters.
Selective emitters are devices for converting thermal energy into narrow band radiation. Most solid state materials have nearly a constant spectral emittance (gray body). The spectral emittance of a rare earth is characterized by several emission bands in the visible and near infrared region resulting from electronic transitions from the lowest excited states.
Selective emitters have been used in thermophotovoltaic energy conversion systems such as those described in U.S. Pat. Nos. 4,584,426 and 5,080,724.
Lasing in rare earths such as neodymium (Nd), holmium (Ho) and erbium (Er) in a host material such as yttrium aluminum garnet (YAG, Y.sub.3 Al.sub.5 O.sub.12) has been achieved using flashlamp or laser diode pumping.